Linear Motor Nonsingular Terminal Sliding Mode Position Control via a Disturbance Observer

The high robustness of the permanent magnet linear synchronous motor (PMLSM) servo system is the key to achieve high-speed and high-precision control of direct drive motion. In this paper, a high-order fast nonsingular terminal sliding mode control strategy for permanent magnet linear synchronous motor based on double disturbance observers (DDO) is proposed. A dual disturbance observer is designed to observe the mismatched /matched disturbances to ensure that the PMLSM system is robust to mismatched/matched disturbances. In addition, a high-order fast nonsingular terminal sliding mode controller (HFNTSMC) is designed to enhance the robustness to disturbance observation errors, and integrate the feedback current into it to realize the overall control of the position, speed and current, and improve the dynamic performance and steady-state performance of the position tracking system. Based on the Lyapunov stability theory, the stability and convergence of the closed-loop system are proved. The experimental results show that the system can effectively improve the tracking accuracy and robustness to uncertainty.